A gas turbine generally comprises a compressor, a combustor, and a turbine. The compressor provides compressed air generated by a plurality of compressor blades to the combustor, wherein the compressed air is high-temperature and high-pressure air. The combustor mixes the compressed air, introduced from the compressor, with fuel and combusts the mixed air. The combusted gas generated from the combustor is discharged to the turbine and the turbine is rotated by the combusted gas, thereby generating power. The generated power is used in various fields such as for the generation of electricity and to drive machinery. The gas turbine is used to drive a generator, an aircraft, a locomotive, and the like.
When the combustion occurs in the combustor to make a combusted gas, the combustion is under high-temperature and high-pressure conditions; thus the combustor is susceptible to High Cycle Fatigue (HCF) resulting from the combustion dynamics. The combustor needs to monitor the combustion dynamics, and an impedance tube with a dynamic sensor is used to monitor the combustion dynamics. The state of the art impedance tube including a dynamic sensor comprises a waveguide having an inner diameter of ⅛ inch for routing because a space to install the dynamic sensor is not available and the dynamic sensor is expensive and sensitive to several factors. However, the dynamic sensor connected to the small inner diameter waveguide has difficulty in sensing high frequencies due to excessive damping.